Proposal on Handling Reph in Gurmukhi and Telugu Scripts

Chapter 9 of the Unicode standard [1] describes the representational model for encoding Indic scripts. Devanagari is described in Section 9.1; the principles of Indic scripts are covered in some detail in the introduction to Devanagari. The descriptions of the remaining Indic scripts were abbreviated highlighting any di erences from Devanagari where appropriate. Some of the problems in this description were clari ed by Public Review Issue #37 [2] which focused on consistent handling of Zero Width Joiner (ZWJ) in Indic scripts. That proposal put forth a set of rules for handling ZWJ and ZWNJ that are applicable across all Indic scripts. The formation of Reph is de ned in Section 9.1, Rules for Rendering, R2 of [1]. Reph is de ned as a nonspacing combining mark glyph form of U+0930 DEVANAGARI LETTER RA positioned above or attached to the upper part of a base glyph form. Basically, Reph is formed when a RA which has the inherent vowel killed by the virama begins a syllable. Not all scripts have Reph; if the script in question has a Reph form, the sequence is rendered with Reph on C. Also, for Devanagari, the sequence is always rendered as eyelash-RA instead of Reph. Devanagari, Bengali, Gujarati, Oriya, and Kannada are listed in [1] and [2] as scripts that have a Reph form. Gurmukhi, Tamil, and Telugu are listed as scripts that do not have a Reph form. Malayalam is described as a script that has Reph in the traditional orthography but not in modern usage. However, both Telugu and Gurmukhi are similar to Malayalam in that Reph was used in ancient texts, but is not used in contemporary writings. While several scripts consistently use Reph (both in modern and historic usage), Gurmukhi, Malayalam, and Telugu have variable usage with respect to Reph and there are special scenarios where users may need to display Reph, typically for reproducing old documents. Unfortunately, there is no mechanism in the standard for users to indicate to a renderer that Reph should be displayed, if possible, in one of these scripts. The intent of this proposal is to specify an encoding mechanism that allows users of Gurmukhi and Telugu to indicate that Reph should be displayed by